System and method for remotely releasing a parking brake on a disabled vehicle

ABSTRACT

A system and method of remotely controlling the parking brake of a disabled vehicle to be towed by a towing vehicle includes using the hydraulic fluid of towing vehicle to control the parking brake operation of the disabled vehicle. The towing vehicle is equipped with a control valve and brake release manifold assembly. The brake release manifold assembly provides a source of hydraulic fluid of controlled pressure. The towing vehicle has means to connect the controlled pressure hydraulic fluid of the towing vehicle to the parking brake system. The towing vehicle also has means to control and monitor the flow of hydraulic fluid to the disabled vehicle in order to either release or apply the brakes when desired.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.11/335,558 filed Jan. 20, 2006 now U.S. Pat. No. 7,452,038.

TECHNICAL FIELD

The present invention is directed to a system and method for remotelyreleasing a parking brake on a disabled vehicle.

BACKGROUND ART

In the prior art, many haul trucks are equipped with springapplied-hydraulic released parking brakes. Some haul trucks are equippedwith an emergency parking brake release system. Often times, theemergency parking brake release system will not release the parkingbrakes due to leakage past the seals in the parking brake chamber. Coldtemperatures and worn brake components can create this leakage problem.Under these circumstances the emergency parking brake release systemtypically does not supply the volume of hydraulic oil/fluid to build thepressure required to seat the seals in the parking brake releasechambers.

Other disabled haul trucks require that a temporary hydraulic power packbe installed to release the parking brakes during towing. This optiondoes not allow control of the parking brakes or monitoring of therelease status of the parking brakes. In the case of an emergency,during towing, the parking brakes can not be reapplied. If there were abreak away, the disabled haul truck would be completely out of controlwith no brakes applied.

Thus, there is a need to provide improved systems for control of theparking brakes of disabled vehicles, particularly heavy duty haultrucks. The present invention overcomes the drawbacks noted above andprovides a method and system that allows for remote control of theparking brake of a disabled vehicle from the towing vehicle in anefficient and effective manner.

SUMMARY OF THE INVENTION

It is a first object of the present invention to provide a method andsystem for remotely controlling the release of a parking brake on adisabled vehicle.

Another object of the present invention is a method and system thatallows the control of parking brake systems for different kinds ofdisabled vehicles.

Other objects and advantages will be come apparent as a description ofthe invention proceeds.

The invention is an improvement in the field of towing disabledvehicles. The invention comprises both a system that allows a disabledvehicle to be safely towed and a method of towing such a vehicle. Themethod aspect of the invention involves releasing or applying a parkingbrake of a disabled vehicle using the towing vehicle. This isaccomplished by providing a source of hydraulic fluid at the towingvehicle and supplying the source of hydraulic fluid to a parking brakesystem of the disabled vehicle. The pressure of the supplied hydraulicfluid is controlled at the towing vehicle so as to release the parkingbrake of the disabled vehicle. The pressure of the hydraulic fluid ismonitored during the towing operation, including the pressurizedhydraulic fluid generated by the towing vehicle and or the hydraulicfluid being supplied to the disabled vehicle that is being towed.

In a preferred embodiment, two levels of hydraulic fluid pressure aresupplied by the towing vehicle to accommodate disabled vehicles withparking brakes systems that use different hydraulic pressures.Preferably, the towing vehicle supplies the hydraulic fluid at onepressure level and the fluid pressure is reduced to a desired level foruse by the parking brake system of the disabled vehicle, with bothlevels of pressure being monitored.

The monitoring step can include displaying the sensed pressures of thehydraulic fluids so that an operator can react if there is a problemwith supply of the hydraulic fluid. An alarm can also be provided thatwould trigger a signal such as sound, light, vibration or anycombination thereof to alert the towing vehicle operator of a problemshould the monitored pressure deviate from a target range of value.

The source of hydraulic fluid can be generated in any manner, but apreferred manner is to use an accumulated source of hydraulic fluid,with the pressure of the accumulated source being maintained within adesired range or at a desired value.

Another preference for the invention is to use a towing vehicleemploying a gooseneck hitch for towing.

The invention also entails, in one embodiment, a system for releasing aparking brake of a disabled vehicle with a towing vehicle to facilitatetowing. The system includes a source of hydraulic fluid provided fromthe towing truck and means for supplying the hydraulic fluid to aparking brake system of the disabled vehicle. Also provided are meansfor controlling and monitoring the supply of the hydraulic fluid to thedisabled vehicle, the controlling and monitoring means located on thetowing vehicle.

The means for supplying the source of hydraulic fluid can be anymechanism that would allow the hydraulic fluid supplied by the towingvehicle to be communicated to the parking brake system of the disabledvehicle, with a preferred way being the use of one or more hoses on thetowing vehicle. Each hose would be adapted with the appropriatecouplings or the like to connect to a parking brake system of thedisabled vehicle for supply of the hydraulic fluid to the parking brakesystem.

While any system can be utilized to provide the necessary and controlledsupply of hydraulic fluid at the towing vehicle, one preferred mode isthe use of an accumulator, the accumulator being in communication withthe source of hydraulic fluid and providing an accumulated supply ofhydraulic fluid to the disabled vehicle that is controlled and monitoredfor towing of the disabled vehicle.

While any means can be employed to control the generation of thehydraulic fluid at the towing vehicle as well as control its flow to thedisabled vehicle, a preferred arrangement as the means for controllingand monitoring comprises a control valve located on the towing vehicle,the control valve being adapted to supply hydraulic fluid via an outputline based on a sensed pressure. An accumulator is employed and adaptedto receive supplied hydraulic fluid from the output line of the controlvalve for supply to the disabled vehicle via an output line. A pressureswitch is also provided that senses pressure in the output line tocontrol the output of the control valve and a solenoid valve is providedthat is adapted to control flow of hydraulic fluid from the output lineof the control valve to the supplying means, preferably by the use of areturn line to a hydraulic fluid tank on the towing vehicle. A pressuretransducer monitors the pressure in the output line and pressure ofhydraulic fluid to the supplying means and a display is located in thetowing vehicle and is adapted to display the monitored pressures fromthe pressure transducers.

While the system could use the hydraulic fluid as generated by thetowing vehicle, another mode uses the hydraulic fluid of the towingvehicle in a reduced pressure condition for the disabled vehicle. In apreferred mode, a pressure reducer in communication with an output ofthe accumulator is provided, with an output line of the pressure reducerin communication with the supplying means. While a single reducedpressure arrangement could be employed, a preferred mode is to use aplurality of pressure reducers, each having a respective pressuretransducer, the plurality of pressure reducers adapted to provide ahydraulic fluid at different pressure levels to accommodate differenttypes of parking brake systems.

The system can also include an alarm associated with each pressuretransducer, the alarm adapted to signal an operator of the towingvehicle when pressure of hydraulic fluid supplied by the towing vehicleor hydraulic fluid supplied to the disabled vehicle varies from a targetrange or value.

The invention also combines the system for releasing the parking brakeof a disabled vehicle with a towing vehicle having a hitch for towing ofa disabled vehicle. Preferably, the towing vehicle is one that employs agooseneck hitch, and more preferably a gooseneck hitch and grab hookassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of one aspect of the invention.

FIG. 2 is a schematic view of another aspect of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention provides a significant improvement in the field of haulingdisabled vehicles. That is, the invention provides a way toindependently control the parking brakes of the disabled vehicle from atowing vehicle. This ability compliments a towing vehicle that is merelydesigned to tow a disabled vehicle. With the invention, the value of thetowing vehicle is significantly enhanced since it can now not only haulthe disabled vehicle but also control the parking brakes of the disabledvehicle in spite of any problems that may exist with the parking brakesystem.

More particularly, practicing the invention allows the operator of thetowing vehicle to monitor the parking brake state of the disabledvehicle and either release or apply the parking brakes from the confinesof the towing vehicle during towing. This yields a significant in termsof safety. For example, in the event of an emergency during towing, thetowing vehicle operator could change the state of the parking brakes ofthe disabled vehicle from a released state to an operative or appliedstate. Another advantage of having the control of the parking brakesystem stem from the towing vehicle is that if the towed vehicle shouldbreak away from the towing vehicle such that the connection between thetwo vehicles would be severed, the loss of hydraulic fluid to theparking brake system would result in a reapplication of the parkingbrakes and stopping of the run away disabled vehicle.

Referring now to FIGS. 1 and 2, the overall intent of the system andmethod of the invention is to remotely release the park brakes of adisabled vehicle such as a haul truck from a towing vehicle, andautomatically maintain the release pressure and allow constant systemmonitoring from the towing vehicle.

FIG. 1 shows one embodiment of the invention, wherein componentstypically found on a towing vehicle are illustrated. In this embodiment,the towing vehicle is a modified haul truck. That is, the haul truck ismodified by having its dump body and hoist cylinders removed, but stillkeeping the existing hydraulic hoist pump on the truck. Then, the haultruck is fitted with a towing package that makes use of the hydraulichoist pump for its operation. One example of such a modified towingtruck is one manufactured and sold by TowHaul Corporation of BozemanMont. The towing vehicle is a multiple use vehicle that can, in onemode, haul disabled vehicles using a gooseneck hitch. This vehicle isalso equipped with a grab hook assembly on the gooseneck hitch thatfacilitates towing of low boy trailers. The towing package involving agooseneck hitch that includes a grab hook assembly is shown in U.S. Pat.No. 5,435,586 to Smith, herein incorporated in its entirety byreference.

The towing package that is used in the modified haul truck is shown inFIG. 1. That is, a high pressure filter assembly 1 is situateddownstream of the hydraulic hoist pump 3 of the haul truck. A flowcontrol assembly 4 designed to control the flow of hydraulic fluid,e.g., between 55-60 gpm, is arranged downstream of the filter assembly1. A control valve assembly 5 is utilized to control the flow ofhydraulic fluid to the various components of the towing package added tothe haul truck.

In the towing package employed in the haul truck of TowHaul Corporation,the control valve is a four section hydraulic control valve with input11 and return 13 designed to operate two slide cylinders (section 12),two apron cylinders (section 14), one grab hook cylinder (section 16),and two or more low boy trailer cylinders (section 18). In the FIG. 1embodiment of the invention, the existing hydraulic control valveassembly 5 is modified to include an additional section 7 with hydraulicfluid output 9 to provide hydraulic fluid to means for controlling andmonitoring the supply of hydraulic fluid to the disabled vehicle.

FIG. 2 shows one embodiment of the controlling and monitoring means assystem 20. The system 20 includes an accumulator 21, e.g., a five gallontype, and a brake release manifold assembly 23. The assembly 23 is shownwith an input line 25 which communicates with the output 9 of thecontrol valve section 7. A check valve 27 is provided at input 25 toprevent backflow to the control valve section 7. A relief valve 29 isalso provided in communication with the input 25 to allow for bypass ofhydraulic fluid back to the tank or reservoir 2 of the hydraulic hoistpump 3 if the pressure in line 25 should exceed a set limit. In oneembodiment, this limit is preferably 2,200 psi, but this limit couldvary depending on the pump 3 and parking brake system requirements ofthe disabled vehicles intended to be towed.

The manifold assembly 23 also includes a solenoid valve cartridge 31(preferably two-position two-way), a pressure switch 33, three pressuretransducers 35, 37, and 39, two pressure reducing cartridges 41 and 43,and means for supplying hydraulic fluid from the manifold assembly 23 toa disabled vehicle. As one example of this means, hoses on hose reelscan be used, and these are shown schematically as 45 and 47. Themanifold assembly also has a return line 48 which is in communicationwith the tank 2.

The manifold assembly 23 is adapted to provide hydraulic fluid atdifferent pressures at outputs 49 and 51 to accommodate differentdisabled vehicles. One way used to accomplish this is the use of a pairof pressure reducing cartridges 41 and 43 and complementary hose reelassemblies 45 and 47 for connection to a desired disabled vehicle. Inthe mining industry, two types of haul trucks are predominant, one madeby Caterpillar® and one made by Komatsu®. The Caterpillar truck normallyoperates at a hydraulic pressure of 600 psi whereas the Komatsu truckoperates at a pressure of 1,500 psi. The manifold assembly 23exemplified in FIG. 2 is designed with connecting or supplying meansadapted for the two different hydraulic pressure requirements. Forexample, pressure reducer 41 would be designed to produce a target 600psi pressure at output 49 with the pressure reducer 43 designed toproduce a target 1,500 psi at output 51.

A control panel is shown schematically as 50, the control panelincluding digital displays 51, 53, and 55 and a switch or other means 57for controlling the operation of the parking brakes on the disabledvehicle. In one embodiment, the switch 57 can be a rocker switch thatmoves between a RELEASE BRAKES position, wherein the parking brakes ofthe disabled vehicle are released or an APPLY BRAKES position, whereinthe parking brakes of the disabled vehicle are applied.

The operation of the embodiment of the inventive system illustrated willnow be described. Prior to the need for towing a vehicle, the controlvalve section 7 would not operate and no hydraulic fluid or electricalpower would be available to the system 20. If the need should arise forthe towing vehicle to haul a disabled vehicle, the appropriate hose 45or 47 would be used and the coupling on the hose end (not shown) wouldbe attached to the appropriate location on the disabled vehicle so thathydraulic fluid can be supplied to the parking brake system of thedisabled vehicle.

With the appropriate hose connected to the disabled vehicle, the switch57 would be set to the RELEASE BRAKES position. This shifts the solenoidcartridge 31 to close communication with the return line 48. With themovement of the switch, power is also applied to the components of thesystem 20 and the pressure switch 33 senses a low pressure in the inputline 25 and sends a signal to control valve section 7 to supplyhydraulic fluid to the system 20. This hydraulic fluid is supplied viaoutput line 9 so as to charge the accumulator 21. The pressure switch 33senses pressure of the hydraulic fluid so as to maintain a pressure ofbetween 1,700 and 2,100 psi in the accumulator 21. When the pressureswitch 33 senses that the pressure is at a desired level, e.g., 2,000psi, it signals to control section valve section 7 to return to itsneutral position and the flow of hydraulic fluid ceases, and the system20 operates on accumulated pressure. The check valve 27 prevents loss ofpressure back to the tank 2, and the relief valve cartridge 29 protectsagainst overpressurization of the system 20. If the pressure in thesystem 20 should fall below a target pressure, the pressure switch 33will sense such pressure loss and signal the control valve section 7 toopen and provide additional hydraulic fluid to the system 20.

The stored and pressurized hydraulic fluid in the accumulator 21provides hydraulic fluid to the pressure reducing cartridges 41 and 43,each set at different pressures as described above. The reduced pressurehydraulic fluid will flow from the output of a selected pressurereducing cartridge that is connected to the disabled vehicle so that thebrakes can be released.

The system 20 also allows the operator of the towing vehicle to controland monitor the supply of hydraulic fluid to the disabled vehicle. Thepressure transducer 35 monitors the hydraulic pressure to theaccumulator 21 and sends a signal to its digital display 51 to alert theoperator of the towing vehicle as to the level of pressure upstream ofthe pressure reducing cartridges 41 and 43. Similarly, each transducer37 and 39 monitors the pressure downstream of their respective pressurereducing cartridges and each sends a signal to its digital display, 53and 55, respectively to alert the operator of the pressure beingsupplied to the disabled vehicle. Each of the displays is designed tomonitor the pressure within a target range and trigger an alarm 61,e.g., audio, visual vibratory, or a combination thereof. Typicalpressure ranges would be 1,700-2,100 psi for display 51 and input line25, 550-680 psi for output 49 for the Caterpillar truck and display 51,and 1,500 to 2,200 psi for output line 51 for the Komatsu truck anddisplay 53. These ranges are exemplary and others could be employeddepending on the particulars of the system 20 and the disabled vehicleto be towed. As a check on the alarm system, the alarm system can bedesigned to temporarily activate once the system initially becomesoperational. Also and while three individual displays are shown, asingle display or display/alarm combination could be employed that wouldreceive signals from each transducer and be able to display thedifferent pressures being monitored.

While a control and monitoring system and method are disclosed thattakes a hydraulic fluid provided at a designated or controlled pressureby the towing vehicle and reduces it to a target pressure for thedisabled vehicle, the control and monitoring system and method could dowithout the pressure reducers. For example, if the disabled vehicle hada parking brake system that used a hydraulic fluid pressure that matchedthat of the towing vehicle, the system could merely provide a hydraulicpressure from the towing vehicle directly to the disabled vehiclewithout the need for pressure reduction. In this embodiment, it may benecessary to regulate the pressure supplied by the accumulator within aparticular range for the disabled vehicle, and the manifold assemblycould employ such a regulator in place of the illustrated pressurereducers. In this mode, the control of the towing vehicle pressure andmonitoring of the pressure of hydraulic fluid supplied by the towingvehicle and the hydraulic fluid supplied to the disabled vehicle wouldstill be maintained using the appropriate pressure sensing devices.

During the towing operation, a malfunction or other problem could occursuch that the alarm would be triggered. In such a situation, theoperator should immediately stop the towing vehicle and investigate thereason for the variance in pressure and take the appropriate correctivemeasures.

If the operator should want to apply the parking brakes of the disabledvehicle, the switch 57 can be moved to the APPLY BRAKES position. Thisshifts the solenoid cartridge 31 to provide communication between thepressurized manifold assembly 23 and the return line 48 therebyreleasing the pressure in the system. The movement of the switch 57would also de-energize the system electrically.

The invention offers a number of advantages over current methods forcontrolling the parking brake of a disabled vehicle. First, the systemautomatically maintains the brake release pressure of the vehicle beingtowed. Multiple pressures can be accommodated using a single system. Oneswitch that is readily accessible to the operator of the towing vehicleis used to either release the brakes or apply the brakes. Using thetowing vehicle's hydraulic system greatly reduces the risk of a runawaydisabled vehicle by a failure in the disabled vehicle's parking brakesystem. The monitoring of the brake release system minimizes thepotential of towing a disabled vehicle with a partially applied parkingbrake.

It should also be understood that the TowHaul Corporation modified haultruck is one example of a towing vehicle that is capable of remotelycontrolling the parking brake operation of a disabled vehicle. However,other towing vehicle systems using different arrangements of hydraulicfluid supply and control could be employed to provide hydraulic fluid toa means for controlling and monitoring the supply of pressurizedhydraulic fluid to the disabled vehicle. For example, another towingtype of towing vehicle and towing package may require a different typeof control valve for operation of the cylinders associated with thelifting arrangement. While the lifting arrangement of the towing vehiclemay vary, the constant is the means associated with the towing vehicleto provide the supply of hydraulic fluid to the disabled vehicle'sparking brake system so that the parking brake operation can bemonitored and controlled from the towing vehicle.

While the brake release manifold is shown supplying two different levelsof pressurized hydraulic fluid for two different types of towingvehicles, it should be understood that it could be made so that itsupplies just one pressure level range of hydraulic fluid or more thantwo different levels.

Also and although the means for connecting the pressurized hydraulicfluid to the disabled vehicle is exemplified as a hose and hose reelwith the appropriate couplings on the end of the hose for connection tothe parking brake system of the disabled vehicle, other types ofconnection means as would be known in the art could be employed. Also,one hose and hose reel assembly could be used to connect to the disabledtruck with the appropriate valving or diverters to connect the singlehose to the appropriate one of pressure reducing cartridge pair.

In addition, the particular components of the brake release manifoldcould be altered providing that: (1) a source of hydraulic fluid isstill supplied to the disabled vehicle; and (2) that the suppliedhydraulic fluid flow can be controlled and monitored from the towingvehicle to allow the operator of the towing vehicle to be able to eitherrelease or apply the parking brakes or take other action when giveninput as to the operation of the brake release manifold system.

The disabled and towing vehicles can be any type of a vehicle.Preferably, the disabled vehicle is a mining haul truck and the towingvehicle is a truck designed to tow these heavy duty hauling trucks. Asmentioned above, one example of a towing vehicle is one that employs agooseneck hitch and grab hook assembly for towing both disabled vehiclesand trailers, e.g., those manufactured by TowHaul Corporation ofBozeman, Mont.

As such, an invention has been disclosed in terms of preferredembodiments thereof which fulfills each and every one of the objects ofthe present invention as set forth above and provides a new and improvedmethod and system for remotely controlling the parking brake of adisabled vehicle.

Of course, various changes, modifications and alterations from theteachings of the present invention may be contemplated by those skilledin the art without departing from the intended spirit and scope thereof.It is intended that the present invention only be limited by the termsof the appended claims.

1. A system for releasing a spring applied parking brake of a disabled vehicle having a service braking system and a spring applied parking brake system with a towing vehicle to facilitate towing comprising: a source of hydraulic fluid, the source of hydraulic fluid being provided in one or more elevated pressure levels at the towing vehicle; means for supplying one of the one or more elevated pressure level hydraulic fluids to the spring applied parking brake system of the disabled vehicle; means for controlling and monitoring the supply of the hydraulic fluid to the disabled vehicle, the controlling and monitoring means located on the towing vehicle so as to control the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle, wherein the ability of supplying the elevated pressure level hydraulic fluid to the disabled vehicle permitting towing of disabled vehicles with parking brakes systems using an elevated pressure parking brake system hydraulic pressure, wherein a single line between the towing vehicle and the towed vehicle is used for both supply and return of the selected hydraulic fluid applied to the spring applied parking brake system and the braking system of the towing vehicle including a parking brake and a service brake, and further wherein the means for controlling and monitoring the hydraulic fluid controls the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle independently of the braking system of the towing vehicle.
 2. The system of claim 1, wherein the means for supplying the source of hydraulic fluid is one or more hoses on the towing vehicle, the hose adapted to connect to the spring applied parking brake system of the disabled vehicle for supply of the hydraulic fluid to the spring applied parking brake system.
 3. The system of claim 1, wherein the controlling and monitoring means includes an accumulator, the accumulator in communication with the source of hydraulic fluid and providing the supply of hydraulic fluid to the disabled vehicle that is controlled and monitored for towing of the disabled vehicle.
 4. In a towing vehicle having at least four tires, a braking system including a parking brake and a service brake, and a hitch for towing of a disabled vehicle, the improvement comprising the towing vehicle including a system for releasing a spring applied parking brake of a disabled vehicle with a towing vehicle to facilitate towing comprising: a source of hydraulic fluid, the source of hydraulic fluid being provided in one or more elevated pressure levels at the towing vehicle; means for supplying one of the one or more elevated pressure level hydraulic fluids to the spring applied parking brake system of the disabled vehicle; means for controlling and monitoring the supply of the hydraulic fluid to the disabled vehicle, the controlling and monitoring means located on the towing vehicle so as to control the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle, wherein the ability of supplying the elevated pressure level hydraulic fluid to the disabled vehicle permitting towing of disabled vehicles with parking brakes systems using an elevated pressure parking brake system hydraulic pressure for controlling the parking brakes on the disabled vehicle, wherein the means for controlling and monitoring the supply of the hydraulic fluid and operating the spring applied parking brake controls the operation of the spring applied parking brake system on the disabled vehicle from the towing vehicle independently of the braking system of the towing vehicle.
 5. The towing vehicle of claim 4 wherein the towing vehicle has a gooseneck hitch.
 6. The towing vehicle of claim 5, wherein the gooseneck hitch includes a grab hook for latching to a low boy trailer. 